BagIt
BagIt is a hierarchical file packaging format designed to support disk-based storage and network transfer of arbitrary digital content. A "bag" consists of a "payload" (the arbitrary content) and "tags", which are metadata files intended to document the storage and transfer of the bag. A required tag file contains a manifest listing every file in the payload together with its corresponding checksum. The name, BagIt, is inspired by the "enclose and deposit" method, sometimes referred to as "bag it and tag it".
myfirstbag/
|-- data
| \-- 27613-h
| \-- images
| \-- q172.png
| \-- q172.txt
|-- manifest-md5.txt
| 49afbd86a1ca9f34b677a3f09655eae9 data/27613-h/images/q172.png
| 408ad21d50cef31da4df6d9ed81b01a7 data/27613-h/images/q172.txt
\-- bagit.txt
BagIt-version: 0.97
Tag-File-Character-Encoding: UTF-8
The general description can be read here
https://en.wikipedia.org/wiki/BagIt
The formal description is here